1. Field of the Invention
The present invention relates to light guides, illuminating devices, and image reading apparatuses, more particularly to a light guide and an illuminating device for use in an image reading apparatus.
2. Description of Related Art
For example, a known conventional light guide is described in Japanese Patent Laid-Open Publication No. 2008-216409. FIG. 10 is a cross-sectional structure diagram of a light guide 500 described in Japanese Patent Laid-Open Publication No. 2008-216409.
The light guide 500 includes a reflective surface 502 and output surfaces 504a and 504b, as shown in FIG. 10. The output surfaces 504a and 504b are in the form of arcs next to each other. Moreover, the reflective surface 502 is provided in a position facing the output surfaces 504a and 504b. Light reflected by the reflective surface 502 is collimated by the output surface 504a or 504b upon exit from the light guide 500.
Incidentally, there is some demand for light to be utilized more efficiently in a light guide.